Contact lenses have been used to improve vision for many years. Early designs of contact lenses were fashioned from hard materials, such as polymethyl methacrylate (PMMA). However, these lenses were uncomfortable and caused various problems for patients because of their relatively low permeability to oxygen. Soft contact lenses which were oxygen-permeable were later developed using materials based on hydrogels. Although hydrogel lenses are extremely popular today, the industry is continuously looking to improve the design of lenses or develop lenses specific to a certain condition.
For example, presbyopia is typically an age-related condition in which the eye's ability to focus on near objects progressively diminishes. The result for many people is the need for varifocal or bifocal glasses. Some of these glasses incorporate lenses that attempt to correct both near and far vision with the same lens. With respect to contact lenses, some people choose contact lenses to correct one eye for near and one eye for far, although side effects can include an interference with depth perception due to the loss of concurrent focusing of one eye in relation to the other eye.
Liquid lens technology has been gaining momentum with respect to use in medical imaging devices, microcameras, and fiber-optic telecommunication systems. A liquid lens uses one or more fluids to create a variable focus lens without any moving parts. In most cases, two immiscible fluids, one an electrically conducting aqueous solution and a nonconducting oil, are provided in a closed device. A hydrophobic coating may be applied to interior portions of the device, for example, to force the aqueous solution into a hemispherical lens-shaped configuration toward a portion of the device not having the hydrophobic coating. In a process called electrowetting, application of very minute direct current voltages across the hydrophobic coating decreases the repellency of the coating. The liquid's surface tension is changed through the process, which changes the radius of curvature in the meniscus, which in turn changes the focal length of the lens. A liquid lens is thus capable of transitioning from a convex (convergent) to a concave (divergent) lens shape with voltages as little as 0.1 microjoules and in just a few milliseconds.
A solution for presbyopia may rest on the ability to create a multiple state liquid meniscus lens that allows a person to control, for example, the zoom in and zoom out capability of the lens. However, the ability to manufacture this type of ophthalmic lens depends on the ability to create and assemble ultra-thin optical quality parts that are not deformed during manufacturing.
Designs of ophthalmic devices in accordance with aspects of the present disclosure rely on using ultra-thin materials that require extreme care in the shaping and handling of component parts. Even if handled with care, ultra-thin parts can often warp, curl, or irreversibly deform. Methods and systems are needed to enable assembly of, for example, a liquid filled ophthalmic device using ultra-thin parts that will not deform during shaping, handling, and assembly.